This invention relates generally to hot-fill polyester containers and more particularly to a PET container of this type provided with vacuum collapse pinch grip indentations.
Thin walled thermoplastic polymeric containers of bottle shape are becoming increasingly recognized as desirable for containing liquids such as processed fruit juices and the like which must be pasteurized and as a result, are placed in the container when hot, namely, above about 180.degree. F. Accordingly, such a container must be of the "hot-fill" type. Hot-fill PET containers are well known and are shown in U.S. Pat. Nos. 4,805,788 and 4,863,046. Such containers are characterized by the fact they are made of a heat set material such as PET with 28-32% crystalinity and they accommodate hot filling and partial evacuation without adverse affects on their appearance. Other hot-fill containers are illustrated in earlier filed U.S. patent application Ser. Nos. 211,464, 452,638 and 492,073 owned by the assignee of this application.
These containers are formed by blow molding biaxially orientable polyethylene terephthalate (PET) resin. The result is containers which have a number of advantages such as being lightweight, having excellent mechanical strength and physical properties and being inexpensive in cost together with the ability to be produced in large numbers.
Because of the lightweight, thin-walled characteristics of such containers, they can be made in large sizes and still be manually handled during storage and dispensing without undue manual effort.
However, the hot-fill containers presently in use have the main sidewall portion of the container of generally tubular shape and are provided with upright side panels which will tend to collapse inwardly after the hot liquid is dispensed into the container so as to accommodate the inevitable volume shrinkage of the liquid in the bottle. As a result, while the containers may be readily carried and tipped for pouring, two hands are often required because of the large diameter of the sidewall portion and the difficulty of gripping the sidewall portion with one hand.
Accordingly, it is the principal object of this invention to provide an improved hot-fill container of the above type having an opposed pair of indentations in the sidewall portion enabling the sidewall portion of the container to the grasped between the thumb and fingers of one hand to thereby enable one handed lifting and manipulation of the container.
It is further object of this invention to provide for hinging support of the pair of indentations on the sidewall portion to thereby enable the indentations to collapse inwardly toward each other to accommodate internal forces tending to collapse the sidewall portion inwardly due to filling of the container with liquid at an elevated temperature and subsequent cooling of the liquid.
U.S. Pat. Nos. 4,804,097 and 4,897,052 show PET containers with hand grip indentations in the side walls. However, the containers in which the hand grip indentations are embodied are not hot-fill containers. They are conventional PET containers for liquor, soft drinks, or the like which cannot withstand being filled with liquid at an elevated temperature. Thus, the present invention utilizes the desirable characteristics of the prior art hot-fill containers and embodies in these containers the pinch grip indentations in the form of vacuum collapse panels which can collapse inwardly of the container due to filling of the container with liquid at an elevated temperature and subsequent cooling of that liquid.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description, the appended claims and the accompanying drawing.